\documentclass{article}
\usepackage{tikz,amsmath}
\usetikzlibrary{arrows.meta}
\usepackage[graphics,tightpage,active]{preview}
\PreviewEnvironment{tikzpicture}
\begin{document}
\begin{tikzpicture}[>=Stealth]
    \draw (0, 0) node [anchor=north] {$a$} -- (3, 2);
    \draw (1, -0.5) node [anchor=east] {$b$} -- (4, 1.5);
\end{tikzpicture}
\end{document}
